Re: more descriptive message for process termination due to max_slot_wal_keep_size

On Fri, Dec 24, 2021 at 5:30 PM Kyotaro Horiguchi
<horikyota(dot)ntt(at)gmail(dot)com> wrote:
>
> Thank you for the comment.
>
> At Fri, 24 Dec 2021 17:06:57 +0900, Masahiko Sawada <sawada(dot)mshk(at)gmail(dot)com> wrote in
> > Thank you for the patch! +1 for improving the messages.
> >
> > >
> > > > LOG: terminating process %d to release replication slot \"%s\" because its restart_lsn %X/%X exceeds max_slot_wal_keep_size
> > > > DETAIL: The slot got behind the limit %X/%X determined by max_slot_wal_keep_size.
> > >
> > > > LOG: invalidating slot \"%s\" because its restart_LSN %X/%X exceeds max_slot_wal_keep_size
> > > c> DETAIL: The slot got behind the limit %X/%X determined by max_slot_wal_keep_size.
> >
> > -
> > LSN_FORMAT_ARGS(restart_lsn))));
> > +
> > LSN_FORMAT_ARGS(restart_lsn)),
> > + errdetail("The slot
> > got behind the limit %X/%X determined by max_slot_wal_keep_size.",
> > +
> > LSN_FORMAT_ARGS(oldestLSN))));
> >
> > Isn't oldestLSN calculated not only by max_slot_wal_keep_size but also
> > by wal_keep_size?
>
> Right. But I believe the two are not assumed to be used at once. One
> can set wal_keep_size larger than max_slot_wal_keep_size but it is
> actually a kind of ill setting.
>
> LOG: terminating process %d to release replication slot \"%s\" because its restart_lsn %X/%X exceeds max_slot_wal_keep_size
> DETAIL: The slot got behind the limit %X/%X determined by max_slot_wal_keep_size and wal_keep_size.
>
> Mmm. I don't like this. I feel we don't need such detail in the
> message.

How about something like:

LOG: terminating process %d to release replication slot \"%s\"
because its restart_lsn %X/%X exceeds the limit
DETAIL: The slot got behind the limit %X/%X
HINT: You might need to increase max_slot_wal_keep_size or wal_keep_size.

Regards,

--
Masahiko Sawada
EDB: https://www.enterprisedb.com/